1. Field of the Invention
This invention relates generally to apparatus for metal grinding and more particularly to apparatus for grinding valves within the valve seats of internal combustion engine.
2. Background Art
Proper operation of internal combustion engines requires seating or sealing of the inlet and outlet valves for the appropriate time duration in the cycle of operation. Failure to properly seal may not only result in inefficient engine operation, but may also result in damage to the engine itself.
Proper maintenance of an internal combustion engine requires periodic reseating of the engine valves. This is normally accomplished by rotating the valve while in contact the valve seat in the presence of an abrasive valve grinding compound. Numerous apparatus have been developed to perform such valve grinding operations. The prior apparatus presently known to Applicant is considered below.
U.S. Pat. No. 2,576,333 to Earll discloses a valve and seat grinding device for an internal combustion engine. A rotatable pulley rotates the valve and operates the two compression springs 26 and 27 which actually move the valve either into grinding engagement with the seat or space the valve from the seat to permit visual inspection. The direction of valve rotation controls the direction of axially movement of the valve and therefore the direction of grinding is not reversible. The non-rotating spring housing formed by the cylinder 16 and cap 17 is held against the manifold flange during operation to properly align the valve and seat.
Jensen U.S. Pat. No. 2,908,120 discloses a grinding apparatus for flow control valves in which the spring force may be adjusted. The grinding wheel is rotated either by hand or a drive motor. A mounting bracket is used to secure the apparatus to the valve house.
German Pat. No. 717,470 also discloses a manually operated valve grinding device having a chuck for securing with the valve stem.
U.S. Pat. Nos. 1,502,005 to Bishir and 1,951,796 to Kulp et al. disclose valve grinding apparatus.
The Bishir apparatus is designed for use on overhead valves and requires removal of the valve and seat case from the engine. The Kulp apparatus provides a guide bearing for centering the valve during grinding.